1. Technical Field
The disclosure relates to a touch panel, and in particular relates to a touch panel having a favorable capability of electrostatic discharge (ESD) protection.
2. Description of Related Art
Based on different sensing methods, touch panels can be categorized into the following types: resistive touch panel, capacitive touch panel, optical touch panel, acoustic-wave touch panel, and electromagnetic touch panel. A capacitive touch panel is characterized by short response speed, good reliability, satisfactory durability, and so forth. Therefore, capacitive touch panels have been extensively applied in various kinds of electronic products. In view of structures and manufacturing methods, capacitive touch panels can be further classified into an additive type and an integrated/in-cell type. In an additive-type capacitive touch panel, sensing series are first formed on a substrate, and the substrate having the sensing series thereon is then adhered to an outer surface of a display. As a consequence, the additive-type touch panel inevitably has a certain thickness. Compared with the additive-type touch panel, an integrated/in-cell type touch panel is more conducive to the slimness and lightness of the display.
However, in terms of fabrication, the integrated/in-cell type touch panel and the additive-type touch panel both encounter the problem of low yield rate resulting from electrostatic discharge. Such a problem is especially crucial to the integrated/in-cell type touch panel. For instance, most of the current integrated/in-cell type touch panels are fabricated by forming a touch-control circuit on one surface of the substrate and then forming a color filter thin film on the other surface of the substrate. While the color filter thin film is being formed, the touch-control circuit is often damaged due to electrostatic discharge. Moreover, when the user touches the integrated/in-cell type touch panel and the additive-type touch with his/her finger, electrostatic discharge may also occur, resulting in the damage of the touch-control circuit.
Since electrostatic discharge is inevitable during the fabrication and use of the touch panel, how to enhance the touch panel's protection against electrostatic discharge is one of the important issues that all designers seek to overcome.